Performance objectives for sanitary napkins or pads include a dry feeling for the wearer, comfort due to appropriate fit throughout the life of the pad, and low leakage from the product.
Most commercially available pads have relatively high leakage rates. These pads may fail as much as 30 percent of the time, and failure rates of about 20 percent are quite common. Such failures are believed to be due to the highly viscous nature of menses and the great variability in delivery volume which results in overloading of the pad in the target area and subsequent leaking. Insufficient distribution of menses is believed to be one of the key causes of the target area overloading.
In the field of urine management in personal care products like diapers, distribution is often provided by materials that have small pores with a narrow pore size distribution.
These materials must move the high volume, low viscosity urine insults out of the target area in a time sufficient for the target area to be able to accept the next insult. The movement of urine may be to relatively remote parts of the diaper overcoming substantial hydrostatic pressure. In contrast, feminine hygiene products experience lower total insult volume but the fluid is of greater viscosity, making it more difficult to move the fluid. Distribution materials must be quite different for feminine hygiene products than for products concerned primarily with urine management.
Previous attempts to provide lower leakage feminine hygiene products include U.S. Pat. Nos. 5,549,589, 5,466,232 and 5,200,248, which discuss distribution structures for menses. None of these references provide the unique combination of attributes of the instant invention.
It is an object of this invention to provide a feminine hygiene products having superior distribution performance to allow movement of menses from the target area and provide comfort, dry feeling, and lower leakage than traditional pads.